The field of application of the invention comprises wrist-worn devices, such as heart rate monitors, wrist-worn computers, or the like. The invention particularly relates to the setting of user-specific heart rate parameter limits in a wrist-worn device.
The evaluation and planning of the intensity of an exercise is important both to a fitness enthusiast as well as a competing athlete. A reliable method for evaluating the intensity is to monitor the frequency of heartbeat, i.e. heart rate, measured from the person""s body. Depending on the target intensity set for the exercise, the user may try to maintain the heart rate within a desired range. For example, in a fat-burning exercise of a long duration, the aim may be to keep the heart rate between 100 and 120 beats per minute, whereas a competing athlete engaged in a high-tempo interval training may aim for example at momentarily raising the heart rate level to 160-180 and then again lowering it to 120-140.
Heart rate is measured from the body using a heart rate monitor. The measurement may be carried out in various ways, for example from electric signals caused by heartbeat to the chest, from a pressure pulse caused by blood on the wrist, or optically from the circulation of blood in the wrist. A common embodiment of a heart rate monitor comprises a transmitter electrode belt to be placed on the chest to transmit measured heart rate information to a receiver unit carried on the wrist, the receiver unit displaying the information to the user. The wrist-worn receiver usually comprises, in addition to a liquid crystal display, keys for the user to input data and sound signalling means. With the keys, the heart rate limits within which the user wishes his heart rate to remain during the exercise are supplied to the heart rate monitor. If the user""s heart rate does not remain within the set limits, the monitor produces a sound signal to allow the user to check his momentary heart rate on the display and to adjust the exercise intensity accordingly.
The prior art solutions for monitoring heart rate limits are not convenient to use. A heart rate value is difficult to read from a liquid crystal display, particularly in the dark. The setting of heart rate limits with the keys is often complicated, difficult and slow.
It is an object of the invention to provide an improved solution for setting heart rate parameter limits in a wrist-worn device. This is achieved with a wrist-worn device comprising a display for showing a heart rate parameter value, such as a heart rate measured from a person""s body or a heart rate variable derived from the heart rate. The display comprises at least two display areas which display areas the wrist-worn device is arranged to employ to show that a heart rate parameter momentarily belongs to a heart rate parameter value range corresponding to the display area and which wrist-worn device comprises at least one sliding means for selecting a desired heart rate parameter value range by mechanically sliding the sliding means to cover at least one display area at a time.
The preferred embodiments of the invention are disclosed in the dependent claims.
The invention thus relates to a novel solution for setting heart rate parameter limits in a wrist-worn device. In this specification of the invention, the term wrist-worn device refers to equipment comprising heart rate measurement functions and the displaying of a measured heart rate or a heart rate variable derived from the heart rate. Heart rate monitors and wrist-worn computers provided with a heart rate measuring function are thus examples of equipment the invention relates to. The heart rate parameters to be displayed for which the limits are to be set include heart rate, average heart rate or rate deviation.
In this context, the term display refers to the parts of the device used for visually displaying an exercise variable value to the user. In a preferred embodiment of the invention, the display is composed of separate display areas. The display is preferably formed on a resilient and flexible circuit board, and each display area corresponding to a specific exercise variable value can be illuminated with a display-area-specific illumination element, such as a LED (Light Emitting Diode). The illumination elements, or light sources, do not necessarily have to be close together, but they may be arranged on various locations on the wristband. The number of the display areas used for displaying the exercise variable values is naturally not limited in invention either. In a preferred embodiment, the topmost layer of the display is made of a translucent plastic to make the light emitted by a display-area-specific light source visible to the user. The light sources may also be placed on the surface of the wrist-worn device, uncoated by the plastic encapsulating the device. The display is preferably a bar display comprising a string of display areas arranged along a substantially straight line with respect to each other in the longitudinal direction of the wristband. A first end of the bar display thus comprises a value range corresponding to the lowest exercise variable values that can be displayed, a second end comprising in turn a value range corresponding to the highest exercise variable values that can be displayed. An exercise variable value can be displayed for example by only illuminating the display area to which the exercise variable value relates. Alternatively, all value ranges lower than said value range are illuminated, in addition to the value range concerned. Instead of a bar display, a display forming an arc can also be used.
The wrist-worn device preferably comprises an electronics unit, which receives the heart rate information from a heart rate transmitter or from the electrodes of the wrist-worn device. The wristband, the display and the electronics unit are preferably integrated to form a single entity, i.e. a uniform piece. Integration as used in this context means that the parts of the device are joined together process-technically during the manufacturing phase, for example by injection moulding, in which the parts are coated with plastic to produce a uniform piece. The parts thus form a wrist-worn device in which the display and the electronics unit can be thought of as integral parts of the wristband with which the device can be attached to the wrist. With injection moulding, the wrist-worn device can be manufactured in a plural number of phases, whereby different plastics with different transparency and colour properties can be used. For example, the part of the wrist-worn device that encapsulates the display is made using transparent plastic.
The heart rate limits are set using mechanical sliding means, i.e. a piece which at least partly surrounds the wristband or the display area and can be slid on the wristband. The sliding means is meant to cover a portion of the display, for example the display areas of the display forming a bar-shaped arrangement which correspond to unwanted heart rate parameter value ranges. If the display areas are in a ring-shaped formation on the wrist-worn device, the device is provided for example with slide protrusions on the surface, on both sides of the display areas, the protrusions allowing the sliding means to be slid on the display areas. In a ring-shaped arrangement, the display areas form a part of a sector, for example, the sliding means being preferably of a corresponding formation. It is apparent that the above solution of slide protrusions can also be applied to a bar display. To ensure that the sliding means stays in place on the desired location on the wristband, it preferably comprises a slot or a toothing that can be engaged with counter pieces provided on the wristband to secure the sliding means in place. The wrist-worn device preferably comprises two sliding means, an upper sliding means for covering an area above the desired heart rate parameter area, and a lower sliding means for covering an area below the desired heart rate parameter area. The user thus aims at keeping the heart rate parameter value, such as heart rate, between the sliding means during the exercise. In a preferred embodiment of the invention, the sliding means are transparent, the light emitted by the light source of the bar display being at least partly visible through the sliding means. In a preferred embodiment of the invention, the sliding means are made in different colours corresponding to the area covered by the sliding means; for example, the upper sliding means may be red and lower sliding means yellow. Alternatively, the heart rate parameter value may be controlled with a wrist-worn device having a single sliding means, which may be green, for example. The sliding means is placed on top of the allowed heart rate area, the transparent sliding means thus allowing the user to control that the heart rate parameter value remains on the display areas covered by the sliding means, i.e. within the desired value range.
An advantage of the invention is that it provides an improved wrist-worn device solution in which the setting of heart rate limits is quick and simple. The solution offers to the user a concrete means for monitoring that the heart rate parameter value remains within the desired value range.